As far as I know this is strictly rumor right now. I heard this awhile ago -- and actually Toni Basil ("Oh mickey you're so fine, you're so fine you blow my mind, hey mickey!") was rumored as Roxie as well. At least she can sing and dance. To the best of my knowledge (note that phrase please), Bianca Marroquin is in talks to return to Chicago after her stint with the tour is over. Very coincidentally, her closing night in Philly on tour, is also Charlotte's closing night on Broadway.
We shall see though.
"You're every gay man's wet dream!" ~ MA
If in Heaven you don't excel, you can always party down in hell...